Hi,
it's probably not significant, but a little annoying: the plugin writes trace info because of a type error (it is also contained in ownedbycats' debug info above):
Code:
Running file type plugin GetFileName failed with traceback:
Traceback (most recent call last):
File "calibre/customize/ui.py", line 176, in _run_filetype_plugins
File "calibre_plugins.getfilename.__init__", line 108, in run
json.dump (dictio_aux, file)
File "json/__init__.py", line 180, in dump
TypeError: a bytes-like object is required, not 'str'
Is that possibly python 2->3 issue?